Machine tool



May 3,

H. FSSENHUSER MACHINE TOOL Filed Nov.. 29, 1938 @La i Iwww Y A Patented May i941 MACHINE Toor.

Herbert Fssenhuser, Augsburg, Qermany, as-4 signor to Maschinenfabrik Augsburg-Nrnberg A. G., Augsburg, Germany,

Germany a corporation of Application November 29, 1938, Serial No. 242,976

In Ge rmany 3 Claims.

This invention relates to machine tools and more particularly to tools for finishing or grinding grooves on the inside of a hollow part.

One object of the invention is the provision of a finishing or grinding tool having a series of surfacing or grinding members which are movable in substantially radial directions in a body member and having means for equalixing the out ward pressurev exerted on the individual surfacing members. 1

Another object of the invention is the provision of a finishing tool for finishing grooves on the inside of a hollow a. body member having a series of independently adjustable carriers on which the surfacing members are arranged, 'independently adjustable slides being provided to move the carriers diiierentially in substantially radial directions in the body member.

Another object of the invention is the pro-` vision of a surfacing tool of the character mentioned, in which the surfacing members are of substantially the same width as the Width of the grooves to be surfaced or polished, the surfacing members being pivotally supported on their re- November 29, 193'! part and comprising spective carriers for movement about axes substantially transverse of the longitudinal axis of the body member, for finishing inclined or helical grooves.

Other objects and advantages ofthe invention will beapparent from the following description,-

the appended claims, and the accompanying drawing, in which:

Fig. 1 is a longitudinal central section through a finishing tool embodying the present invention; Y

Fig. 2 is a transverse section on the line 2-2 of Fig. 1; and

Fig. 3 is a diagrammatic illustration of the pressure equalizing connection to the various slides.

Referring more particularly to the drawing by reference numerals. the finishing tool of the present invention comprises a shank I to which is screwed a shell 2, the shell enclosing a ball bearing 3. which provides balls on opposite sides of an end disk l which is secured to the body member 5 of the tool by means of a nut 8. The body y5 of the tool is thus capable of rotation with respect to the shank I, and which provides for axial reciprocatory movement of the body 5.

Within the body 5 of the tool and secured therevto by means of a pin 1 is a guide rod or bolt 8 upon which a number of slides 9 are arranged, the slides 9 being positionedannularly about the guide bolt and extending radially and capable of endwise movement on the guide bolt. They are held against turning on of a guide box II in which the end portions of the slides are slidably positioned. The guide box II is secured to the bolt 8 by means o f pin il.

The slides 9 are adapted to be moved by means which applies equal pressures to the various slides, such means as herein shown comprising a cable or string I2 which is carried over rollers or pulleys- I3 arranged on the various slides 9 and rollers I4 which are carried by a spring pressed sleeve or pressure member IB. The ends of the cable l2 are connected to the pressure member i6 by means of a screw I5. Pressure member I6 is actuated by means of a' springA Il which. bears at one end against a. thrust plate II adjustably threaded so that the tension ofthe spring Il may be varied. The pressure axial movements on the'bolt 8 vand is held against rotation .on the bolt by means of a pin I9 the opposite ends of which are slidable in slots extending axially in the pressurev member I6. Spring I8 an; lts opposite end presses against a part 20 which is secured as by threads to the end of the body member 5. This part 20 also serves to hold a guide ring 22 fast on the body member 5, a disk or washer 2i being provided between the part 20 and the guide ring. The cable -I2 is arranged over the' rollers or pulleys I3 and I4 in a zig-zag relationship so that when the pressure member I6 is moved Ito the left, see Fig. 1, by the spring Il, an equalized v tension prevails in the various parts of the cable slides 9, thus yieldingly urging them towards the left axially of the bolt 8 with equal forces. The force applied to the slides 9 may be adjusted by tarrning the 'thrust plate I1 on the pressure memr 6. Fixed at the opposite end of each of the slides 9 is a threaded pin 23 f which extends freely Ithrough annular disk 25. A nut 2l is threaded on each pin 23 on the outer side of the disk and the disk` bears on a flange provided on a large nut 26 which is adjustably threaded on the body member 5. A key or wedge 21 holdsthe disk 25 against rotation on the body member 5 but permits axial movements of the disk. When the nut 26 is moved outwardly on the body member,

retracted positions against the tension of they the guide bolt by means on the pressure member Il v member I6 is guided for means of screw spring I9.' When the nut 26 is turned in the oppostte direction the disk 25 'is moved to the left and then separates from the nuts 24 so that the slides 9 may be moved differentially by the spring .IBL

Each slide 9 cooperates with anca'rrier 28 which carries a surfacing member or grinding stone 32 preferably of rectangular form. The several carriers are slidably arranged andguided for axial movements in the body member 5. On each slide 9 there is a pair of inclined camming surfaces cooperating with correspondingly arranged camming surfaces. on the respective carrier 28 so that as the slide 9 is moved axially to the left as viewed in Fig. 1, the carrier 28 is moved radially-"l5 outward in the body member. Expansible ring springs 29 extend around the various carriers 28 and yieldingly restrain radially outward movements of the carriers and return them to their inner positions when the slides 9 are in their normal retracted positions.

The surfacing members or polishing stones 32 are mounted gn holders 3| which are rotatably or pivotally mounted on trunnions 30 provided on the carriers. The width of the grinding stones 32 conforms to the width of the grooves to be finished in the inside of the hollow part in which thegrooves to be finished are arranged, and since the stones can turn about the axis of the trunnions 30, it is possible to polish or finish helical or inclined grooves as the stones may faces of the grooves. The movement of the various carriers and their respective operating slides differs from one another lif the depth of the various grooves is not uniform, although the pressure exerted by the several carriers is .the same. All of the grooves in the work are therefore simultaneously finished or-ground as the driving arbor is reciprocated. After the finishing operation has 'been completed, the slides 9 are retracted by unscrewing the nut 26, permitting the carriers l28 to be retracted by means of the expansible ring springs 29 so that the tool can then be read- A ily removed from the hollow body.

adapt themselves to the angularity of the grooves in the grooved part.

The tool is adapted to grind or. finish a number of grooves on the inside of a hollow part and although the depth of the grooves may vary to some extent, and even if the depth of a groove or grooves is different at different pointsalong Aits length,.the finishing or accurate grinding or polishing of all the grooves may take place simultaneously since the carriers adapt themselves in dividually and differentially to grooves of different depths and apply equal radial forces to the Work. In -accordance with prior arrangements, the shallower grooves of a grooved part must first be ground down to a depth equal to the deeper grooves before the :finishing operations on the deeper grooves can be started even though the depths of the unfinished grooves may not vary from a desired or correct measurement in excess of the limit of tolerance. Thus a very accurate machining or preiinishing operation has been necessary so that the grooves may be all of exactly the same depth before the finishing operation is started or else a very large amount of close or final finishing has been required. It will be seen however that in accordance with the present invention, the individual carriers on which the surfacing members are independently arranged are relatively adjustable in radial direc- `tions but with equal outward pressures so that the close finishing of all of the grooves may proceed simultaneously without regard to the depth in the different grooves.

In a finishing operation the tool, which is fastened to a suitable reciprocatoryl driving arbor,

While the form of apparatus herein described constitutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise form of apparatus, and

that changes may be' made therein without departing from the scope of the invention whichis defined in the appended claims.

What is claimed is:

1. A finishing tool of the character described for finishing grooves on the inside of a hollow part, comprising a body, a series of carriers adjustable independently of one another in said body for substantially radial movement therein, each carrier having a plurality of inclined camming surfaces, an axially movable slide for each is introduced into the work, with the various slides in ytheir retracted or normal position and heldso against the action o'f the spring I 8 by the of said carriers slidably carried by said body and having camming surfaces for moving its respective carrier outwardly when the slide is moved axially in one direction, spring means for moving all of said slides in said one direction, and means for equalizing the forces applied by said spring means to the several slides.

2. A finishing tool of the character described for finishing grooves on the inside of a hollow part, comprising a body, a series of carriers adjustable independently of one another in said 'body for substantially radial movement therein, an axially movable slide for each of said carriers for individually adjusting the carriers radially of the body, a pressure member operable axially of the body, and a cable connecting said-pressure member to the various slides and having pressure equalizing connections therewith.

3. A finishing tool of the character described comprising a body, a series of carriers adjustable independently of one another for substantially radial movement in said body, an axially movable slide for each of said carriers and operably mounted in said body for adjusting the carriers 

